Fig. REF  shows a map with \(V_\text{G12}\)  and small DC bias. Fig. REF  shows a similar map, but with only \(V_\text{G1}\)  being swept and \(V_\text{G2}\)  fixed at 0.9 V, a trajectory that minimizes the amount encounters with charging resonances. In both cases, at low \(V_\text{G12}\)  and away from the coulomb blockade charging levels, tunneling conductance is observed: \(G\)  is strongly suppressed at zero bias, and coherence peaks are seen near \(V_\text{DC} = \pm \Delta /e\) . For comparison with experimental conductance, the gap value extracted from \(T_C\)  in the leads is indicated by the dashed line in Fig. REF , REF , and REF . This is consistent with the expectation of tunneling across an SN interface [1]}. Applicability to our case can be rationalized by considering the SNS junction as two SN interfaces in series [2]}. The gradual increase of subgap conductance with \(V_\text{G12}\)  is consistent with a decrease in tunnel barrier strength [1]}.
